certifiably vs gradely

certifiably

adv
  • Genuinely 

  • With the potential for certification. 

  • To a great extent. 

  • Undoubtedly, demonstrably. 

gradely

adv
  • properly, really 

adj
  • excellent 

  • of a person; decent, well-meaning, respectable 

  • handsome, fair 

  • real, proper 

How often have the words certifiably and gradely occurred in a corpus of books? (source: Google Ngram Viewer )